Collapsible ladders



April 22, 1969 E. o. SCHEERER COLLAPSIBLE LADDERS Filed April 12, 1968 FIG.4

W Y R R E E N 7 R MH 0 C T N T I A FIG.I

United States Patent 3,439,776 COLLAPSIBLE LADDERS Ernest 0. Scheerer,777 Vaughn Ave., Toms River, NJ. 08753 Filed Apr. 12, 1968, Ser. No.720,827 Int. Cl. E06c 1/383 US. Cl. 182-160 4 Claims ABSTRACT OF THEDISCLOSURE A collapsible ladder wherein the rungs are pivotally attachedto the upright legs and are so deformed at their ends as to prevent themfrom swinging in one direction, and a releasable pivoted lug is providedon one rung to prevent all the rungs from swinging in the oppositedirection when the ladder is in extended condition for use. To collapsethe ladder into a narrow but slightly longer mass, the said lug is swungout of the way and one leg is moved longitudinally with respect to theother to swing the rungs said opposite direction and thus bring the legsinto mutual contact.

The accompanying drawings illustrate embodiments of the invention, and,referring briefly to the drawings:

FIG. 1 is a front elevational view, with parts broken away and partly insection, of a novel collapsible ladder.

FIG. 2 is a fragmentary enlarged view, with parts broken away and partlyin section, of the ladder in fully collapsed condition.

FIG. 3 is a sectional view taken on the line 33 of FIG. 1.

FIG. 4 is a sectional view taken on the line 44 of FIG. 1.

FIG. 5 is a sectional view taken on the line 55 of FIG. 1.

FIG. 6 is a perspective view of the rung which is provided with thepivoted stop or locking lug.

Referring in detail to the drawing, the numerals 10 and 11 designate theopposed upright legs of the ladder which, together with other partsdescribed below, are preferably made of a light weight material such asaluminum or an alloy of aluminum. The legs are in the form of channelmembers, that is, substantially U-shaped in cross-section, being made upof the channel bases 12 and the opposed wings 13. The legs arepositioned with the channel bases 12 on the outer side, that is, withthe open channels facing toward each other.

A plurality of ladder rungs 14 are provided, spaced verticallyequidistant. Each rung is roughly S-shaped, as shown, and includes astraight intermediate section or body portion 15 having at one end adownwardly extending deformation or nose 16 and at the other end anupward extension, deformation or nose 17, both noses being at rightangles to the straight body portion 15.

At the junctions of the noses 16 and 17 with the ends of the straightbody portion 15 of each rung, a pivot pin 18 extending through the rungand the channel wings 13 pivotally attaches the rung to the ladder legs10 and 11. The outer edges 19 of the noses 16 and 17 contact the channelbases 12 when the ladder is in the extended condition shown in fulllines in FIG. 1. It is thus obvious that, as so far described, the rungsare constrained against swinging in a clockwise direction, FIG. 1, butthey are obviously free to swing in a counter-clockwise direction. FIG.1 illustrates in phantom an intermediate position of the swinging of therungs in the counterclockwise direction.

In order to constrain the rungs from swinging in a counter-clockwisedirection, FIG. 1, when the ladder is in extended condition for use, thefollowing provision 3,439,776 Patented Apr. 22, 1969 is made. At leastone rung 14a above the bottommost rung is preferably provided in theform of a channel member throughout its length; the upwardly extendingnose of this rung is shown at 17a. The pivot pin 18 of this rung, at thejunction of the nose 17a with its straight intermediate body portion,also passes through the wings 20 of the rung, as well as through theupper end or head of an elongated lug 21 which is thus pivotallysuspended from the pin 18 between the wings20. The length of this lug issuch that, when freely suspended, its lower extremity contacts andregisters upon the upper extremity of the nose 17 of the next lower rung14, as seen in FIG. 1.

It is now obvious that with the lug 21 in the position thereof shown inFIG. 1, the rungs cannot be swung in a counter-clockwise direction, forif a force to do so is applied, the lowermost nose 17 will be blockedagainst counter-clockwise swinging by the obstruction provided by theleg. For in order to swing counter-clockwise, the said lower nose 17must move through an are which, at the beginning, slopes upward in adirection from right to left. But the lug cannot yield to such a forcesince it is blocked against longitudinal movement by its pivot pin 18.Thus the ladder is secure against collapsing when in the extendedcondition.

In order to collapse the ladder in the direction of the topmost curvedarrows, FIG. 1, the lug 21 must first be swung to the left, in thedirection of the bottommost curved arrows. The lug may then be swunginto the channel of the rung 14a where it will be concealed, as shown inFIG. 2, and the two legs 10 and 11 may then be brought together with allthe rungs registering between the wings 13 of the legs. When collapsed,the ladder has a greatly reduced width and a slightly increased length,as is obvious.

Although the rung 14:: has been shown channel-shaped, it together withthe other rungs need not necessarily be so in order to provide acollapsible ladder of the kind disclosed. It is so that the lug 21 mayregister within the channel of the rung 14a and thus not obstruct closecoming together of the legs 10 and 11, that the rung 14a is shownchannel-shaped. All of the lugs may of course be made channel-shaped ifdesired, especially for strength, but the collapsible ladder asdisclosed herein and defined in the appended claims will functionwhether or not any or all of the rungs are flat or channel-shaped.

What is claimed is as follows:

1. A collapsible ladder consisting of two upright legs and a pluralityof equidistantly spaced rungs pivotally attached to said legs, saidrungs including straight body portions and end deformations extendingfrom said body portions beyond the pivot axes thereof and normallyengaging said legs and constraining the rungs. from swinging in onedirection about their pivots while permitting swinging of the rungs inthe opposite direction, one of said rungs above the bottommost runghaving pivoted locking means suspended from one end thereof engageablewith the corresponding end of the next lower rung for releasablyblocking said next lower rung from swinging in said opposite direction.

2. A collapsible ladder according to claim 1, said deformations whichare positioned adjacent one of said legs comprising noses extendingdownward at right angles to said body portions and said deformationswhich are positioned adjacent the other of said legs comprising nosesextending upward at right angles to said body portions, said lockingmeans being suspended from that end of said one of said rungs which hasthe nose thereon extending upward from the body portion thereof, saidlocking means comprising a lug having a length such that when the ladderis in extended condition the lower end of the lug 3 engages the upperend of the corresponding upwardly extending nose on said next lowerrung.

3. A collapsible ladder according to claim 2, said legs beingchannel-shaped in cross-section and positioned with the open channelsfacing toward each other, said rungs having a width less than the Widthof said channels, means for pivotally attaching said rungs to said legsas aforesaid consisting of pivot pins supported in the opposed wings ofsaid channel-shaped legs whereby when the ladder is in collapsedcondition said rungs are contained partly within the channel of eachleg.

4. A collapsible ladder according to claim 3, said one of said rungsbeing channel-shaped in cross-section throughout the length thereof,said lug having a width less than the width of the channel of said oneof said rungs whereby said lug is registrable within said lastnamedchannel when the ladder is collapsed.

References Cited UNITED STATES PATENTS 350,047 9/1886 Dunn 182-160785,810 3/1905 Koopman 182-160 1,215,455 2/1917 Wine 182-159 1,783,68612/1930 Williams 182-160 REINALDO P. MACHADO, Primary Examiner.

